Genetic variability of two Italian indigenous chicken breeds inferred from microsatellite marker analysis

The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes.Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE.The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds.Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability.As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks. The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes. Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE. The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds. Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability. As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks.

本研究旨在利用国际通用的微卫星位点（microsatellite loci）集（AVIANDIV-FAO），解析意大利西北部皮埃蒙特地区的Bionda Piemontese与Bianca di Saluzzo两个家禽品种的遗传结构及遗传变异。通过比对商业品系与其他意大利本土品种的差异，验证本研究结果，为保护项目的实施提供理论依据。本研究采用MolKin软件内置的分析方法，评估各鸡群对遗传变异的贡献度；通过固定指数（fixation index）与雷诺遗传距离（Reynolds genetic distance）开展群体比对分析；采用STRUCTURE软件的聚类流程，估算最优种群划分数量。分子生物学分析结果表明，现有饲养管理模式可能阻碍了随机交配，进而导致各鸡群出现近交与异质性。在此方面，Bionda与Bianca呈现出群体亚结构，且相较于其他欧洲大陆品种，它们与英国品种的亲缘关系更近。Bionda和Bianca属于等位基因数量与期望杂合度均处于较高水平的欧洲品种。皮埃蒙特地区的这两个品种与其他种群存在显著分化。皮埃蒙特家禽既区别于商业品系，也不同于其他意大利本土品种，且保留了较高水平的遗传变异。与其他本土品种类似，Bionda与Bianca未来可为家禽产业带来原创性贡献。由于当前鸡群管理缺乏规范，采用集体规划的恢复方案至关重要。通过建立高效的种鸡替换交流机制与交配计划，加强育种者之间的联系，是控制近交、规避群体亚结构以及提升鸡群内遗传变异的有效途径。本研究旨在利用国际通用的微卫星位点（microsatellite loci）集（AVIANDIV-FAO），解析意大利西北部皮埃蒙特地区的Bionda Piemontese与Bianca di Saluzzo两个家禽品种的遗传结构及遗传变异。通过比对商业品系与其他意大利本土品种的差异，验证本研究结果，为保护项目的实施提供理论依据。本研究采用MolKin软件内置的分析方法，评估各鸡群对遗传变异的贡献度；通过固定指数（fixation index）与雷诺遗传距离（Reynolds genetic distance）开展群体比对分析；采用STRUCTURE软件的聚类流程，估算最优种群划分数量。分子生物学分析结果表明，现有饲养管理模式可能阻碍了随机交配，进而导致各鸡群出现近交与异质性。在此方面，Bionda与Bianca呈现出群体亚结构，且相较于其他欧洲大陆品种，它们与英国品种的亲缘关系更近。Bionda和Bianca属于等位基因数量与期望杂合度均处于较高水平的欧洲品种。皮埃蒙特地区的这两个品种与其他种群存在显著分化。皮埃蒙特家禽既区别于商业品系，也不同于其他意大利本土品种，且保留了较高水平的遗传变异。与其他本土品种类似，Bionda与Bianca未来可为家禽产业带来原创性贡献。由于当前鸡群管理缺乏规范，采用集体规划的恢复方案至关重要。通过建立高效的种鸡替换交流机制与交配计划，加强育种者之间的联系，是控制近交、规避群体亚结构以及提升鸡群内遗传变异的有效途径。